Method of treating gas.



v No. 731,412. PATENTED JUNE 16, 1903.

0. N. GULDLIN.

METHOD OF TREATING GAS. APPLIOATION FILE-Ii mugs/1900. RENEWED MAY 1a, 1903.

10 MODEL.

UNITE STATES Patented June 16, 1903.

PATENT FFICEt METHOD OF TREATING GAS.

SPECIFICATION forming part of Letters Patent No. 731,412, dated June 16, 1903. Application filed March 12,1900. Renewed May 18, 1903. Serial No. 157,668. (N0 Specimens.)

To all whom it may concern.-

Be it known that I, OLAF N. GULDLIN, a citizen of the United States, residing at Fort Wayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Methods of Treating Coal-Gas to Prevent Loss of Illuminants; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. same.

This invention relates to the treatment of coal-gas during the purifying and particularly the condensing operation to prevent loss of volatile hydrocarbon illuminants by absorption by the tar.

The object of the invention is to so regulate and control the temperature of the gas that practically all of the tar may be first separated without permitting absorption by the tar of the volatile illuminants and to subse quently reduce the temperature to the most favorable degree for eifective extraction of ammonia or its compounds in the washing and scrubbing operations.

My invention involves the stepping-down method'of condensation,with the intermediate extraction of tar and the final extraction of ammonia.

In the condensation and purification of coal-gas very little attention has been paid to the proper temperature for most effectively and economically extracting the tar. If the temperature is too high, the extraction is incomplete, permitting tarry particles to pass on with the gas, and if the temperature is too temperature in the extraction of tar and the subsequent extraction of ammonia these difficulties have been overcome and greatly improved results secured inactual. practice.

I will now describemy method of treating gas in connection with suitably arranged apparatus, illustrated in the accompanying drawings, in which-- Figure 1 represents an elevation, partly in section, of condensers, tar -extractor, ex-

hauster, Washer, scrubbers, drain-tanks, &c. Fig. 2 represents a top plan view of the same.

The bench of retorts 1, the hydraulic main 2, and the gastake-otf pipe 3 are of the usual wellknown construction. The gas leaves the hydraulic main at a temperature of from 140 to 160 Fahrenheit, and in order to reduce it to the proper temperature for the effective and economical extraction of the tar I pass it first through my primary tubular air-condenser 4. This condenser is constructed with upper and lower tube-sheets 5 and 6, which are connected by the verticalair-tubes 7. In practice the condenser 4 is set upon a hollow foundation providing an interior airduct 8 for permitting the air to freely pass up through the tube 7. At top this condenser is provided with a hood and stack 9, in which latter is placed a regulating-damper 10 for controlling the amount of air passed through the tubes, according to the make of gas and to the temperature of the outside air. It is important that the temperature of the gas be here controlled and uniformly maintained, so that it will leave the condenser at a temperature not less than from to Fahrenheit and preferably between about 100 to Fahrenheit. The gas-takeoff pipe 3 connects with the upper part of the shell of condenser 4., and the gas is passed around and in contact with shell and air-tubes 7 and passes out from the lower end of the shell into the exhauster 11, which draws the gas from the hydraulic main through the condenser and discharges it into the tar-extractor 12, which may be of any suitable form; but preferably I use what is known as a Pelo-uze and Audouin tar-extractor. Part of the tar is separated from the gas in the primary condenser. The remaining tar is separated from the gas by impact in small streams against plane surfaces or plates in the Pelouze and Audouin tarextractor. No ammonia liquor or washingwater is used at this stage of the operation; but the temperature of the gas is carefully and uniformly maintained at between 100 to 115 or Fahrenheit, so that practically all the tar shall be extracted from the gas, while none of the volatile hydrocarbon illuminants will be absorbed by the tar at such temperature in this operation. If the temperature were allowed to rise too high,

much of the tarry particles would rem ain suspended in the gas and would in the subsequent cooling and scrubbing operation still absorb illuminants, which would be precipitated with the tar, thereby reducing the candle-power of the gas. If the temperature were allowed to fall below 90 during the operation of extracting tar in the extractor, a large percentage of the volatile illuminants would be absorbed by the tar, resulting in a reduction of the candle-power of the gas. It is to be noted that it is not my purpose to extract ammonia or ammonia liquor at this stage of the operation, as I can much more effectively and economically extract the tar by maintaining the gas at a uniform temperature between 95 to 115 Fahrenheit, the most efficient temperature within this range for operation of tar-extractor being determined in practical operation, depending 011 heats of retorts in which the coal is carbonized as well as quality of coal used and leaving the extraction of the ammonia to a subsequent operation after the gas has been cooled to approximately 60 Fahrenheit.

My method abovc' set forth is termed a dry process of extracting tar by mechanical impact or precipitation as distinguished from a wet process or a washing operation in which water or am moniacal liquor might be v used and in which the tar would be separated in the objectionable condition of an emulsion.

A pipe 13 connects the tar-extractor 12 with the top of my second tubular air-condenser 14, having the same construction as condenser 1. A pipe 15 connects the lower part of the shell of condenser 14 with the upper part of the multitubular water-condenser 16, which is of a well-known construction.

The gas in passingthrough the condensers 1-1 and 16 will be reduced to a temperature approximating 60 Fahrenheit, which is the proper temperature for entering the Washers and scrubbers for elimination of ammonia. Pipe 17 connects the lower end ofcondenser 16 with washer 18, which may be of any wellknown construction, but preferably the improved washer for which a patent, No. 677,865, has been granted to me; and a pipe 19 connects the Washer with the lower end of the primary scrubber 20, which-in turn is connected by pipe 22, leading from its upper end to the lower end of the secondary scrubber 21. Outlet-pipe 23 at the'top of scrubber 21 will in practice connect With the purifier. (Not here shown.)

The scrubbers 20 and 21 will be filled with coke, wooden or metallic slats, or similar material in the usual manner and will be sup plied at the top with Water and ammonia liquor in the usual manner. In the washer and the two scrubbers the ammonia and its compounds are extracted from the gas while it is at a temperature of about 60 Fahrenheit. The primary scrubber 20 connects at .its lower end by an-overfiow trap-pipe 20 with the washer 18 for supplying weak ammonia-water in which the gas is treated in the washer. The washer connects by an overfi0w-pipe with the drain-pot 25. The scrubbers 20 and 21 also connect with the drainpot 24. Ammonia liquor flows from the pot 24 into the pot or tank 25. The ammoniawat'er pump 27 connects, by means of pipe 26, with the drain-tank and pumps the ammonia liquor through pipe 28 into the top of the primary scrubber 20. In practice fresh water will be supplied to the top of the scrubber 21 by a pipe or tipple or feeding apparatus. (Not here shown.)

A tank 29 serves as a receiver and separator for tar, light oil, and ammonia-water and in practice will have outlets for'these difierent products to wells or tanks for the same.

A separator-tank 30 is placed adjacent to the retorts and to the primary condenser, and with such tank is connected a tar-pipe 2 from the hydraulic main and a drain-pipe from the primary condenser or compensator. In this tank 30 a considerable amount of caustic ammonia will be contained in the ammonia liquor separated from the tar and oil, and such caustic ammonia is passed by pipe 31 into the draintank 25, Where it mixes with the ammoniawater, and is pumped thence into the top of the first scrubber 20 orinto washer 18, or both, where it assists materially in removing carbonic acid and sulfur compounds from the gas.

A pipe 32 conducts tar from the separator 30 to the separator 29, and a pipe 33 connects tank 25 with the separator 29.

ICO

In the construction of a gas plant I make the three condensers 4, 14, and 16 of a combined capacity to reduce the maximum make of gas from about Fahrenheit in the hydraulic main down to about 60 Fahrenheit in the Washers and scrubbers, where the ammonia is eliminated.

My tubular air-condenser 4 being provided with a regulating-damper 10 is adapted for uniformly controlling the temperature of the various volumes of gas, Which may vary from day to day or month to month; If a comparatively large volume of gas is being passed through the condenser, then the damper 10 is more widely opened and a larger amount of air is passed through the tubes. Again, if the temperature of the outside air is higher then a larger quantity is passed through the tubes.

By means of this primary condenser, thereduction to 60 Fahrenheit in condenser 16,

when it will be in the best condition forextracting ammonia during the washing and scrubbing operations. I also may provide a second pump to connect with the separator 30 to pump the ammonialiquorin same,containingalarge amount of caustic ammonia, directly into washer 18, as may prove desirable in the removal of CO and sulfur impurities and prevent obstructions to the scrubbing material of scrubber 20. I may also in place of scrubbers 20 and 21 use any usual style of rotary scrubbers or additional washers after washer 18.

I preferably use for preliminary and secondary condensers 4 and 14 the tubular aircondensers shown, it being generally admitted that air-condensers are the most suitable for the first stages of condensation in coalgas manufacture, where a gradual and slower treatment is desirable; but it is evident that what is termed a Water-condenser,similar in design to 16, can be used, especially for larger works, in which case the regulation of temperature will be effected by regulating the water-supply to same, the same principle of proportional sizes of condensers before and after removal of tar being maintained.

The regulation of air or water to the condensers is usually done by hand in my apparatus, guided by thermometers connected to the pipe at convenient and suitable points of observation; but I may also arrange for such operation byautomatic means, such as is embraced in usual thermostat arrangement, by which the respective dampers or water-supply valves are operated automatically to maintain a fixed temperature.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The method of treating coal-gas for the removal of tar, ammoniacal liquor and other by-products, and preventing loss of volatile illnminants which consists in cooling said gas and regulating said cooling operation at a temperature above 90 Fahrenheit, thereby removing part of the mechanically-suspended tar, then, by dry mechanical impact or precipitation, extracting the remaining tar.

2. The method of treating coal-gas for the removal of tar, ammoniacal liquor and other by-products, and preventing loss of volatile illuminants which consists in cooling said gas and regulating said cooling operation at a temperature above 90 Fahrenheit, thereby removing part of the mechanically-suspended tar, then, by dry mechanical impact or precipitation, extracting the remaining tar, and

subsequently cooling the gas and extracting the ammonia at a lower temperature.

3. In the treatment of coal-gas, the hereindescribed method of removing the tar and preventing loss of illuminants, which consists in gradually cooling the gas as delivered from the generator and maintaining it at a regulated and determined temperature above 90 Fahrenheit, and extracting the tar by dry mechanical precipitation, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

OLAF N. GULDLIN.

I/Vitnessesz ERNEST F. LEVY, THOMAS J. CREGHTON. 

